The present invention relates to rotary tools and, more particularly, to chucks which quickly grasp and release tools within the chuck.
In both consumer and professional power tools such as drills, a chuck is commonly used to retain the cutting tool within the drill. Ordinarily, the chuck includes three jaw members which apply circumferential retaining forces onto the tool. The chuck includes a sleeve which is normally rotated clockwise or counter-clockwise in order to release or tighten the jaw members. The sleeve ordinarily includes threads which mate with thread portions on the jaw members so that as the sleeve is rotated, the mating threads axially move the jaw members in the desired direction.
While these types of chucks are satisfactory for retaining cutting tools in the chuck, they have some disadvantages. One disadvantage is that the chuck sleeve must be constantly rotated in order to open or close the jaw members in order to accommodate several different size diameter tools. This continuous rotation is time-consuming and burdensome. Accordingly, it would be desirable to overcome these disadvantages.
The present invention provides the art with a chuck which enables quick loading and unloading of the cutting tool. The jaw members are spring biased which enable a cutting tool to be moved axially into the jaw members by applying an axial force onto the tips of the jaw members which, in turn, forces the jaw members to open, enabling the tool to enter the jaw members. The jaw members bias back around the cutting tool. The chuck sleeve is rotated, to lock the jaw members around the cutting tool.
In accordance with a first aspect of the invention, a chuck comprises a body member which includes a bore to receive a cutting tool. A plurality of jaw members, which retain the tool in the bore, are axially biased in the body member. A mechanism to lock and clamp the jaw members on the cutting tool is coupled with the jaw members and the body. The mechanism applies a biasing force onto the jaw members. The force enables the jaw members to slide on the body. The jaw members move between a gripping and locking position where the cutting tool is secured in the jaw members, and a position where the jaw members enable egress and ingress of the cutting tool into and out of the jaw members. The locking and gripping mechanism further includes a first and second plurality of rings and a sleeve surrounding both the plurality of rings. The first plurality of rings lock the mechanism in position on the body. The second plurality of rings exert a force on the jaw members to grip the cutting tool in the bore. A coil spring is coupled between the sleeve and the plurality of rings to apply a biasing force, which sets the axial location of the rings to correspond to a given diameter of the cutting tool. Alternatively, the locking and gripping mechanism includes a first ring to lock the mechanism on the body and at least one second ring to exert the locking force on the jaw members. The first ring has at least one engagement member extending radially inward to engage a groove on the body to rotationally lock the first ring on the body. The first ring includes a cam surface to engage the second ring to force the second ring forward to exert the gripping force on the jaw members. The second ring includes a cam member contacting the cam surface. Also, a third ring may be included which includes the cam surface. The body may include a plurality of circumferential partial grooves and at least one axial groove. The circumferential grooves may be helical. The sleeve surrounding the rings may include an axial slot on its inner peripheral surface to receive projections from at least one of the rings. Upon rotation of the sleeve, one of the rings rotates to lock the mechanism (stack of rings) in position on the body and then a second ring exerts a force on the jaw members to grip the tool.
In accordance with a second aspect of the invention, a power tool is provided which includes a chuck. The chuck has a body member which includes a bore to receive a cutting tool. A plurality of jaw members, which retain the tool in the bore, are axially biased in the body member. A mechanism to lock and clamp the jaw members on the cutting tool is coupled with the jaw members and the body. The mechanism applies a biasing force onto the jaw members. The force enables the jaw members to slide on the body. The jaw members move between a gripping and locking position where the cutting tool is secured in the jaw members and positioned where the jaw members enable egress and ingress of the cutting tool into and out of the jaw members. The locking and gripping mechanism further includes a first and second plurality of rings and a sleeve surrounding both the plurality of rings. The first plurality of rings lock the mechanism in position on the body. The second plurality of rings exert a force on the jaw members to grip the cutting tool in the bore. A coil spring is coupled between the sleeve and the plurality of rings to apply a biasing force, which sets the axial location of the rings to correspond to a given diameter of the cutting tool. Alternatively, the locking and gripping mechanism includes a first ring to lock the mechanism on the body and at least one second ring to exert the locking force on the jaw members. The first ring has at least one engagement member extending radially inward to engage a groove on the body to rotationally lock the first ring on the body. The first ring includes a cam surface to engage the second ring to force the second ring forward to exert the gripping force on the jaw members. The second ring includes a cam member contacting the cam surface. Also, a third ring may be included which includes the cam surface. The body may include a plurality of circumferential partial grooves and at least one axial groove. The circumferential grooves may be helical. The sleeve surrounding the rings may include an axial slot on its inner peripheral surface to receive projections from at least one of the rings. Upon rotation of the sleeve, one of the rings rotates to lock the mechanism (stack of rings) in position on the body and then a second ring exerts a force on the jaw members to grip the tool.
Additional objects and advantages of the present invention will become apparent from the detailed description of the preferred embodiment, and the appended claims and accompanying drawings, or may be learned by practice of the invention.